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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Westinghouse Quiver - A simple and safe system for the complete handling and storing of failed BWR and PWR fuel rods and fragments - 17049

Background: Extracted leaking fuel rods from fuel assemblies have been stored in the spent fuel pools at the Nuclear Power Plants for many years. Sending those fuel rods to an intermediate storage has been very difficult due to the uncertainty of the technical requirements. The Westinghouse Quiver is a container that can be used from the first moment when the leaking fuel rod is extracted from the Fuel Assembly. The leaking fuel rod can be placed in the Westinghouse Quiver. When the Quiver is filled, it can be sealed and dried and then treated as a regular fuel assembly during intermediate storage and final repository. Purpose of System: The purpose of the system is to store leaking fuel rods, broken rods and fuel rod fragments leak tight in the fuel pool and after vacuum drying and permanent sealing at an intermediate storage facility. The Quiver is designed to be fully compatible with a regular fuel assembly. That means all handling of the Quiver in a Nuclear Power Plant, during transportation or storage is also identical to that of a regular fuel assembly. Fulfilling these criteria together with functional testing, the Quiver is considered acceptable for long time storage of leaking fuel rods, both in dry or wet condition. The Quiver has been qualified in Switzerland for use in the spent fuel pool, intermediate storage, and for a final repository. The system will be implemented as well in Sweden during 2016-2019. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Regulatory inspection of the provision of disposability assessment and waste packaging advice in the UK to provide confidence that higher activity waste stored on licensed sites will be suitable for safe handling, transport and disposal - 15088

Radioactive Waste Management Limited (RWM), the developer and future operator of a geological disposal facility (GDF) in the United Kingdom, operates a disposability assessment process to minimise the risk that current conditioning and packaging of higher activity wastes (HAW) will result in packages incompatible with geological disposal in the future. Specialists in nuclear and environmental safety from the Office for Nuclear Regulation (ONR) and the Environment Agency (EA) in 2013/14 completed an inspection of the RWM's process of disposability assessment. The inspection gave the regulators confidence that RWM has in place a systematic process to provide an important means of reducing risks associated with waste packaging in advance of an operational GDF and that the process of disposability assessment is providing the necessary information for licensees to assure future HAW disposal to the GDF. This work forms part of our continuing programme to review RWM's work related to geological disposal of higher activity radioactive waste (HAW). (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

The challenge: Safe management on spent and disused sealed radioactive source in Thailand - 15654

When sealed radioactive sources are no longer in use, they should be returned back to the country of origin. However, most of them could not be returned to the country of origin, therefore the safety management of spent and disused radioactive source is need. Thailand Institute of Nuclear Technology (TINT) where is as the national waste management center, has the duty to ensure on the safety and the security for long term storage of spent and disused sealed sources before final disposal. The Radioactive Waste Management Center at TINT, is authorized to operate treatment, conditioning and storage of radioactive waste. This paper will describe the proper operational procedures on characterization technique, identification of unknown sources, volume reduction technique, re-packaging, registration and record keeping of spent and disused radioactive source. The successful results exhibit that the record keeping of spent and disused source is developed, and the national inventory of spent and disused source is up to date. This paper would confirm the safety management of radioactive waste in Thailand. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Large Cask, Small Building, AREVA's Safe MLLW Disposal Solution Despite Facility Limitations - 16295

In order to begin decommissioning of a 1950's research reactor, Class C Mixed Low Level Waste (MLLW) had to be removed from the facility and disposed of. The AREVA TN RAM cask, designed and licensed for shipping Type B waste packages, was chosen as the most appropriate shipping solution. Due to the building layout, crane capacity and pool size, the standard TN RAM cask loading process could not be utilized. Unique solutions and approaches had to be developed to complete the project. AREVA designed a smaller liner insert that would house the four MLLW components in a single waste package to solve the problems related to crane capacity and physical pool dimensions. AREVA also designed and fabricated a shield bell to provide radiation shielding while moving the liner insert from the reactor pool to the cask that was staged adjacent to the reactor pool. The AREVA team worked with the disposal facility to cover requirements for disposal of Class B MLLW. This included designing spacers filled with inert material to fulfill the requirement for maximum 10% void space in the waste package. This disposal method for Class C waste met the requirements of macro-encapsulation. Therefore, no additional treatment action was required when disposing of Class C MLLW. AREVA's solution provides a model for disposing MLLW requiring macro-encapsulation in a single waste package. This solution also provides a model for how to adapt large shipping casks and liners to smaller aging commercial, DOE or research facilities. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Proven Safe and Effective Process for the Treatment of Bulk Sodium at Shutdown Reactors and Research Facilities - 18601

Elemental sodium is an alkaline metal that reacts when exposed to air or water. This reaction is exothermic in nature and presents the risk of attendant fire as well as hydrogen generation. Within the United States sodium was used in liquid metal fast breeder reactors (LMFBR) during the 1960's and 70's as a heat transfer medium for commercial, experimental and prototype reactors as well as for nuclear energy related research and development experiments due to the element's good thermal conductivity. Shutdown of these reactors and the end of these experiments present a challenge to decommissioning teams as the wastes associated with each project have different characteristics affecting treatment based on the sodium's origin as well as different volumes requiring treatment. French CEA (Commissariat a l'Energie Atomique) and FRAMATOME worked together in the 1980's to develop a treatment process called the NOAH (NaOH - sodium hydroxide) process for the disposal of large volumes of bulk sodium. This paper provides an overview of the treatment process, details past uses of the technology and discusses the process' applications within the United States Department of Energy complex. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

The Safe Guards Analysis Toolbox for Non-Proliferation Modeling

As nuclear technology becomes more widely available outside of nuclear weapon armed nations, the importance of preventing the illicit development of nuclear weapons has increased dramatically. A system of nuclear safeguards prevents proliferation; stopping the diversion of nuclear material from civilian facilities for the construction of nuclear weapons. These safeguards function through a combination of accountancy measurements that confirm the locations and amounts of nuclear material, and physical security at every nuclear facility. Safeguards Analysis (SGA) is a computational tool-kit developed using the MATLAB Simulink software suite that simulates a system of nuclear safeguards. The code allows users to examine current safeguards systems for weaknesses and to pinpoint the best locations for improvement. Developed as a modular framework, SGA does not directly model material flows, and relies on an outside code for this information. Instead, it represents a series of safeguards measurements that represent the values inspectors would see. Furthermore, SGA is designed to be modular in design, allowing the user to construct as complex or simple a model as needed: simulating an entire fuel-cycle comprising multiple facilities to a single measurement. SGA's use of outside codes for its material flow information makes it applicable to any model available to the user, as opposed to previous work that applied only to a single scenario. This paper discusses the initial development of SGA and the testing of these modules. The tests described in this paper demonstrate that the different pieces of SGA currently work as intended. Future work on the toolbox will develop and test SGA against a more realistic and complicated scenario using the various tools available in SGA. SGA currently has the pieces to perform analysis on safeguards systems, but needs to be tested on large, multi-MBA, systems to ensure the code is capable of handling such large models, to see the effect large models have on calculation speed, and if further work is needed to improve code efficiency. (authors)

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

Continuous measurement of boron concentration in nuclear power plants: why is it essential for safe and efficient operation? - 318

As a neutron-absorber, Boron 10 plays a significant role in nuclear power plants as it is used in order to control reactivity in the core, together with control rods. For that reason; it is a key parameter that has to be controlled. In a similar way, it is crucial to be able to detect a boron dilution in the primary circuit, as it would causes severe damages if not detected and controlled. Thus, it comes as evidence that a boron concentration monitoring system is a key for every nuclear power plant. Consequently, it becomes important to provide plant operators with a boron concentration measurement issued by a reliable, redundant, classified and qualified system, with high accuracy and short response time. In order to cover this need, Rolls-Royce has designed Boronline{sup R}, the latest generation of boron meter, which provides nuclear power plant operators with a permanent record of boron concentration of primary circuit by way of continuous sampling and real-time measurements. Boronline takes part of a new generation of Advanced Sensors and Measurements Technologies. In this paper, boron meter role, main functions and measuring principles will be detailed, as well as technical characteristics of the new generation of boron meter will be presented. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2015

Design, development and utilization of the new LLNL inherently safe subcritical assembly (ISSA) - 14510

Following de-inventory of high security materials from LLNL, a new subcritical assembly for training and detector development purposes was designed and built. This paper describes the safety features inherent in the assembly design and accomplishments related to development, simulation and utilization of the new assembly. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Recycling facility periodic safety review: Application of a methodology used for the nuclear criticality safety review of geometrically safe or favorable equipment - 14610

In France, for all fuel cycle facilities, the reference safety frame is continuously adapted to take into account technical developments such as changes in process and/or maintenance operations. Every ten years according to French law, the facility operator is required to launch a process of Periodic Safety Review (PSR), whose conclusions are sent to the Nuclear Safety Authority (NSA). This PSR is split in two parts: first, a review of the facility to its safety documentation and authorization, second, a safety reassessment. Actually, this PSR takes account for topics (actual aging for instance) which require several years of feedback from experience to be integrated in safety evaluations, or which cannot be done on a daily basis (documentation reorganization). It also incorporates the new regulatory safety requirements. A specific methodology was developed for the first PSR of UP3-A since the publication of the law. UP3-A is a used fuel reprocessing facility of La Hague plant. This methodology, adapted for large plants with numerous process and fissile media, is based on a two-step approach intending to focus the analysis on the real hard spots. First, 'sensitive' systems are identified. Second, a specific review is performed on these systems. After a reminder of the methodology, this paper presents the results of its application on the UP3-A scope. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗